Leveling device



L. E. BLANCHETT LEVELING DEVICE Dec. 14, 1937.

Filed May 13, 1936 2 Sheets-Sheet l F Z QM java Jeff.

INVENTORd BY W W ATTORNEYS.

Dec. 14, 1937. L. E. BLANCHETT LEVEL I NG DEVICE Filed May 13, 1936 2 Sheets-Sheet 2 JzzZ/ W fllmakff I N EN TOR.

9 ATTORNEYS.

Patented Dec. 14, 1937 UNITED Y STATES- muss:

PATENT osrice LEVELING DEVICE Application May 13, 1930, Serial No. 79,5

My invention relates to new and useful improvements in leveling devicesand more particularly to leveling devices ior large power excavators, and still more particularly to that level- 6 responsive element of such leveling devices as controls the jacks or other similar elements thereof.

In this respect, my invention is an improvement on one element of the invention shown and described in the copendlng application of Paul S. Stevens for improvements in Leveling devices, filed October 16, 1936, Serial No. 165,883, and owned by my assignee.

The Stevens invention, thusidentifled, is specifically applied to large excavators which have four independent sets of caterpillar traction, one of which is mounted at each of the four corners of the'base; each set supporting its corner of the base by means of an electrical, mechanical, or

hydraulic jack. It is desired to control the automatic action of these jacks, by means of a levelresponsive controlling device.

The most obvious control element would be a pair of pendulums, swinging in vertical planes at right angles to each other, and each such plane being parallel to the plane which contains two of the jacks. Each pendulum would swim; between two electrical contacts, closing circuits to control the jacks.

30 It is desirable to have the leveling device be sensitive to a change of level of so little as one degree of arc. But the vibrations of a large excavator of this type, and the sudden tilts due to hooking the dipper into the bank, and then jerk- 35 ing on the hoist rope or on the dipper handle,

with the hoist winch or the boom engine respecv tively, set up disturbances which are eflectively many times the amount of the one degree change of level for which I wish to correct. 1

40 Accordingly I have a situation which is very similar to that existing in the most recent etherdriit experiments of Michelson and Morley, in which the probable error of each observation was of a size about 100 times the observation. Such 5 a large error can be eliminated by making thousands of observations; but, in the case of a machine such as that under contemplation, which must act instantly and automatically upon a single observatioman error larger than the ob- 5o servation, or even an error commensurate with the observation, would be fatal.

The obvious solution of this difliculty would be to retard the pendulum by means 01 dashpots. -But, in actual practice, this turned out to be 55 wholly impractical. Most of the bad vibrations a! i use which we would wish to dam out, are harmonically periodic. The eil'ect o the dashpots was merely to slow up the pendulum, until finally the pendulum was vibrating at the same periodic rate, 180 difl'erent in phase from the vibration oi 6 the base. Thus the dash'pots result in doubling the disturbance, rather than in eliminating it.

Two types oi mercury pendulum have been in use in the pricr art, but neither oi these showed any advantage over the above described ineiiec- 1 tive device. One of these two types employed a long tube curved in a vertical plane, with the ends higher than the middle. The flow of mercury to one end of the tube or the other, in response to changes of level, closed electrical con- 15 tacts in the end in question. in the other type, a short tube containing mercury tipped, responsive to the iiow of mercury or to some other weight, thus closing contacts in one end or the other of this tube. I

In view of all this ineffective prior 'art, it is the principal object or my invention to devise a pendulum switch which shall be sensitive to very slight changes ln'level, while remaining insensitive to jars and vibrations. I

In addition to my principal object, above stated,

I have worked out a number of novel and useful details, which will be readily evident as the description progresses.

My invention consists in the novel parts, and in the combination and arrangement thereof, which are defined in the appended claims, and of which one embodiment is exemplified in the accompanying drawings, which are hereinafter particularly described and explained.

Throughout the description, the same reference number is applied to the same member or to similar members. a

Figure 1 is a perspective view, partly cut away, of the base of an excavator possessing a leveling system which includes the device of my invention.

Figure 2 is a perspective view of my complete device, slightly enlarged from the showing of Figure 1, but still not completely detailed.

Figure 3 is a plan view, enlarged a little iurther, but still somewhat conventionalized, of the table and box of Figure 2.

Figure 4 is a side elevation, still further enlarged, 0! one of the fourcontrol elements of Figure 3', taken along the line 4-4 of that figure.

Referring now to Figure 1, we see that H is the main base oi. the excavator or other machine, to which it'is intendedto apply my invention. This base is supported, by means of tour hydraulic jacks II, on four caterpillar traction units i3, which may be propelled by any convenient means, not shown.

Associated with each jack, there is a pump P, driven by a motor M, and certain valves (not shown) all of which are operated and controlled.

through certain electric interlocks (notshown) which constitute the subject-matter oi the copending Stevens application, already referred to.

This control is effected by the control apparatus, designated by I4 in Figure l, and which will now be described. I

Turning now to Figure 2, we see that, from beams I5 of base ii, there are 'pivotally suspended three parallel vertical rods l6 of equal length, which in turn pivotally support triangular table II, on which is secured box l8, holding the nerve-center of my control apparatus.

Turning now to Figure 3, we see that the floor of box l8 supports two inverted T-beams l9, which cross each other at right angles.

- Each T-beam supports, at each end thereof, by means of plate 20, a cylinder 2|, and its associated parts, each pair of such cylinders being connected by pipe 22, containing valve V.

- The box i8 is so oriented that each pair of cylinders 2| lies in a horizontal line parallel to the plane of the two jacks l2 which it controls.

opens by tilting), pivoted at 30, and secured in desired position by means of adjusting screw ii. A counterweight 32 may be added, so that arm 24 will be evenly balanced. y, a

' The pipe 22 of each pair of cylinders 2|, and

the space in each cylinder below its piston 26, is

filled with mercury, or other convenient fluid. The operation of my invention is as follows. Horizontal jars are inefiective to influence -my device, due to the method of its suspension by rods Valves V are sufllciently constricted, so as to eliminate surges. A partially filled U-tube, even with such a constriction, would set up some degree of surging; but the combination of a fully filled tube with pistons at its ends, and mercury switches actuated thereby, eliminates this undesirable phenomenon.

Furthermore, the'combination of my pipe 22 cylinders 2|, arms 24, and tilting switch 29, is in effect a lever which multiplies the .angular displacement of the main base II by the ratio that one half the length of pipe 22 bears to the distance from point 25 to point 28 on arm 24. Without this lever-eflect, a displacement so small as 1 could not actuate switch 29.

A single double-acting tilting switch, and associated elements, actuated by one piston, is to be considered as covered by the terms of any claim calling for a pair of single-acting switches, and associated elements.

Having now described and illustrated one form of my invention,I wish it to be understood that my invention is not to be limited to the specific form or arrangement of parts hereinbefore de- "scribed, except in so far as such limitations are specified in the-appended claims.

I claim: v

1. In a control for a leveling device, the combination of: two level-responsive control means,

each responsive to change of level in a vertical plane at right angles to that of the other; and

roma? means suspending the above-described apparatus from the device to be leveled, so as to permit shifting in all directions in parallel relation thereto.

2.'In a control for a leveling device, the combination of: a level-responsive control means, responsive to change of level in a vertical plane; and means suspending the above-described apparatus from the device to be leveled, so as to permit shifting in all directions in parallel relation thereto. l

3. In a control'i'or a leveling device,'the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; means to constrict the pipe at will to any desired degree; a tilting element with respect to each piston, tiltably attached thereto; a mercury switch carried by each tilting element; and a second set of two cylinders, pistons, pipe, constricting means, two

tilting elements, and two mercury switches, disposed at right angles to the first set.

4. In a control for a leveling device, the combination of: two cylinders, on substantially thev same level; pistons therein; a. pipe connecting the cylinders below the pistons; means to constrict the pipe at will to any desired degree; a tilting element with respect to each piston, tiltably attached thereto; a mercury switch carried by each tilting element; a second set of two cylinders, pistons, pipe, constricting means, two tilting elements, and two mercury switches, disposed at right angles to the first set; and means suspending the abovedescribed apparatus from the device to be leveled, so as to permit shifting in all directions in parallel relation thereto.

5.'In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; means to constrict the pipe; a tilting element with respect to each piston, tiltably attached thereto; a me!"- cury switch carriedby each tilting element; and a second set of two cylinders, pistons, pipe, constricting means, two tilting elements, and two means, two tilting elements, and two. mercury switches, disposed at right angles to the first set; and means suspending the above-described apparatus from the device to be leveled, so as to permit shifting in all\ directions in parallel relation thereto. I

7. In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; a. tilting element with respect to each piston, tiltably attached thereto; a mercury switch carried by each tilting element; and a second set of two cylinders, pistons, pipe, two tilting elements, and two mercury switches, disposed at right angles to the -flrst set.

8. In a control for a leveling device, the combination of: two cylinders, on substantially the.

same level; pistons therein; a pipe connecting the cylinders below the pistons; a tilting element with respect to each piston, tiltably attached thereto; a mercury switch carried by each tilting element; a second set of two cylinders, pistons. pipe, two tilting elements, and two mercury switches, disposed at right angles to the first set; and means suspending the above-described apparatus from the device to be leveled, so as to permit shifting in all directions in parallel relation thereto.

9. In a control for a leveling device, the combination of two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; means to constrict the pipe at will to any desired degree; a switch, actuable by each piston; and a second set of two cylinders, pistons, pipe, constricting means, and two switches, disposed at right angles to the first set.

10. In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; means to constrict the pipe at will to any desired degree; a switch, actuable by each piston; a second set of two cylinders, pistons, pipe, constricting means, and two switches, disposed at right angles to the first set; and means suspending the above-described apparatus from the device to be leveled, so as to permit shifting in all directions in parallel relation thereto.

11. In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; means to constrict the pipe; a switch. actuable by each piston; and a second set of two cylinders, pistons, pipe, constricting means, and two switches, disposed at right angles to the first set.

12. In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; means to constrict the pipe; a switch, actuable by each piston; a second set of two cylinders, pistons, pipe, constricting means, and two switches, disposed at right angles to the first set; and means suspending the above-described apparatus from the device to be leveled. so as to permit shifting in all directions in parallel relation thereto.

13. In a control for a leveling device, the combination of: two cylinders. on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; a switch, actuable by each piston; and a second set of two cylinders, pistons, pipe. and two switches, disposed at right angles to the first set.

14. In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; a switch, actuable by each piston; a second set of two cylinders, pistons, pipe, and two switches, disposed at right angles to the first set; and means suspending the above-described apparatus from the device to be leveled, so as to permit shifting in all directions in parallel relation thereto.

15. In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; means to constrict the pipe at will to any desired degree; a tilting element with respect to each piston, tiltably attached thereto; and a switch, actuable by tilting, and carried by each tilting element.

16. In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; a tilting element with respect to each piston, tiltably attached thereto; and a switch, actuable by tilting, and carried by each tilting element.

17. In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; means to constrict the pipe at will to any desired degree; a tilting element with respect to each piston, tiltably attachcd thereto; a switch, actuable by tilting, and carried by each tilting element; and means suspending the above-described apparatus from the device to be leveled, so as to permit shifting in all directions in parallel relation thereto.

18. In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; a tilting element with respect to each piston, tiltably attached thereto; a switch, actuable by tilting, and carried by each tilting element; and means suspending the above-described apparatus from the device to be leveled, so as to permit shifting in all directions in parallel relation thereto.

19. In a control for a leveling device, the combination of: two cylinders, on substantially the same level; pistons therein; a pipe connecting the cylinders below the pistons; a tilting element with respect to each piston, tiltably attached thereto; and a switch, actuable by tilting. and carried by each tilting element; the pipe and the tilting elements being so proportioned as to materially multiply the tilt of the tilting element, in proportion to the tilt of the pipe.

LUTHER E. BLANCHETT. 

